Inside View: March 2010

February 28, 2010

Written by Gary Jones

Within 20 years, the global population will be around nine billion people. Demand for agricultural produce will likely double.

Current estimates are that agriculture consumes 70 per cent of the Earth’s freshwater supplies and is the major user of land. “According to Energy Resource, by 2030 farmable land per capita will drop to just a third of what it was in 1950. The World Water Council predicts in just a decade we will need 17 per cent more water than is available to provide adequately for the populace.”1

So, what will the future of greenhouse production look like? Here are some suggestions reported from various sources recently. Some are futuristic ideas and may not happen at all. Others are happening now.

In its 2009 competition for students’ design concepts for future appliances, Electrolux announced “a robotic greenhouse for Mars. ‘Le Petit Prince’ (Little Prince) is a robotic greenhouse concept that is specially designed to help the future exploration and expanding population when we colonize Mars. This intelligent robot carries and cares for a plant inside its glass container, which is functionally mounted on a four-legged self-transporting pod.”2 Its job is to search for the optimum place to receive enough sunlight and nutrients and report its movements to fellow greenhouse robots.2

VERTICAL GREENHOUSE PROJECT IN SURREY?
Closer to home, the rural-urban conflict issue builds. The commercial-scale “vertical greenhouse” concept, such as that designed by Dr. Dickson Despommiers, has been widely reported. It may even be that a demonstration vertical greenhouse will be built in Surrey, British Columbia, very soon.

Other projects are already more tangible. The “Sahara Forest Project,” which is “running demonstration plants in Tenerife, Oman and the United Arab Emirates, envisages huge greenhouses in Western Australia with concentrated solar power (CSP), a technology that uses mirrors to focus the sun’s rays, creating steam to drive turbines to generate electricity.”3 For renewable energy, nothing beats directly using sunlight, and since this technology is already proven at large facilities in North America, combining this with food production has potential.

Elsewhere, greenhouse designers in the Netherlands set out plans some years ago for commercial-scale floating greenhouses. In densely populated regions near significant bodies of water, this is something to consider. All the more so if the population also lives on floating cities, as proposed, and water levels rise as predicted due to climate change. Floating greenhouses and residential “streets” have already been built by Dura Vermeer in Maasbommel, the Netherlands. “The Science Barge” is a 400-square-metre, floating steel-decked barge moored in Manhattan, supporting a demonstration “sustainable urban farm” glasshouse. These structures could fit in practically all major Canadian cities, and could reduce pressure on conflicting land use needs.

GREENHOUSE CLUSTERS MAXIMIZE COGEN POTENTIAL
Back on terra firma, large-scale “greenhouse clusters” concentrating economies of scale for energy production are becoming commonplace. “Thanet Earth,” for example, is a new $137-million, 90-hectare (220-acre) facility producing 15 per cent of the U.K.’s greenhouse vegetables. On-site combined heat and power (CHP – cogen) provides electricity for the greenhouses and packhouses with the surplus sold into the grid. In the Netherlands, greenhouses are also going “double-deck,” with growing areas situated above purpose-built packhouse/office facilities to reduce building footprint.

Being major consumers of energy and fresh water, the future of greenhouses may well comprise closed systems (numerous examples already exist) using energy from renewable sources, such as geothermal, photovoltaic, wind power, biomass, and anaerobic digestion.

New types of coverings may well include photo-selective plastics (already available) and transparent photovoltaic glass, currently being developed in the Netherlands. Lighting will likely come from low energy LEDs, and multiple crops per season with yields of up to 400 kg/m2 are predicted.4

Combining that with fish-rearing in aquaponic systems such as that researched at Brooks, Alberta, and Green Q’s Dutch Horticulture Improvement Centre, the future looks interesting for greenhouse food production. ■

Gary Jones is Chair of Production Horticulture at Kwantlen University, Langley, B.C. He sits on several industry committees and would welcome comments at
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